In this paper, the surface of Cu film was treated with formic acid vapor and solution for Cu low temperature bonding. After formic acid vapor/solution treatment, Cu film surface oxide was reduced, and surface became rougher. For formic acid vapor treatment, with the increase of treatment time, Cu film surface was reduced gradually at 200°C, surface roughness and particle size became bigger. For formic acid solution treatment, the reduction of the surface of the copper film was the most abundant when the solution concentration is 50%. After the treatment with formic acid solution, the surface roughness and particle size of copper film increase significantly. As the formic acid solution on the surface of copper film has a certain role in corrosion, using formic acid solution treatment, better surface reduction and rougher surface for Cu film were obtained. By contrast, using formic acid vapor treatment, surface reduction is not so good, but surface is smoother than that treated by formic acid solution. Cu/Cu direct bonding was realized at 200°C after formic acid vapor/solution treatment. Using formic acid vapor treatment, Cu/Cu bond strength is about 18.2 MPa, which is higher than that using formic acid vapor treatment.

中文翻译：

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甲酸蒸气/溶液低温键合处理铜膜表面的研究

在本文中，用甲酸蒸汽和溶液对Cu膜的表面进行了处理，以实现Cu的低温键合。甲酸蒸气/溶液处理后，Cu膜的表面氧化物减少，表面变粗糙。对于甲酸蒸气处理，随着处理时间的增加，Cu膜表面在200℃下逐渐减小，表面粗糙度和粒径变大。对于甲酸溶液处理，当溶液浓度为50％时，铜膜表面的还原最丰富。用甲酸溶液处理后，铜膜的表面粗糙度和粒径明显增加。由于铜膜表面的甲酸溶液具有一定的腐蚀作用，因此采用甲酸溶液处理，获得了更好的表面还原性和铜膜的粗糙表面。相比之下，使用甲酸蒸气处理时，表面还原效果不是很好，但是与用甲酸溶液处理后的表面相比，表面更光滑。甲酸蒸气/溶液处理后，在200°C下实现了Cu / Cu直接键合。使用甲酸蒸汽处理时，Cu / Cu键强度约为18.2 MPa，高于使用甲酸蒸汽处理时的强度。